German Offenlegungsschrift 3,614,770 discloses an anti-lock brake system in which the wheel deceleration and the wheel slip are integrated for a predetermined time and the results of integration summed. If the sum exceeds a limit, a pressure reduction pulse is produced and the results of integration are at least partially erased; preferably, a predetermined number of measured values are integrated, the measured value already taken into consideration the longest being oxcluded upon taking into consideration a new measured value (time window).